New NASA Hubble Space Telescope images of the distant planet Neptune show a dynamic atmosphere and capture the fleeting orbits of its satellites. The images have been assembled into a time-lapse movie revealing the orbital motion of the satellites.

Planet Galatea -- Galatea is the fourth known moon of Neptune, named after the the Nereid of Greek legend.
It was discovered in 1989 by Voyager 2 and very little is known about it. It is irregularly shaped and shows no sign of any geological modification.
Since its orbit is below Neptune's synchronous orbit radius it is slowly decaying due to tidal forces and will one day break up into a planetary ring or impact on Neptune's surface.
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Discovery
Discovered by Voyager 2...